Hopping robots are described in U.S. Pat. Nos. 7,263,955; 7,775,305; 6,247,546; and 6,328,002 as well as in pending application Ser. No. 13/066,276 filed Apr. 11, 2011, all of which are incorporated herein by this reference. A combustion powered linear actuator is used to provide hopping mobility
In the designs of U.S. Pat. No. 7,263,955, the actuator piston is releasably latched to the actuator body via a magnet which is exposed to the environment can become fouled when the piston extends. In cases where the piston cannot be retracted or will not stay in the retracted position because of magnet fouling, operation of the robot via a hopping action would be hindered.
Moreover, the combustion gas exhaust ports of the designs depicted in the '995 patent are not sealed when the piston is retracted which can lead to contamination of the components of the actuator in harsh environments. Such contamination may result in a failure to function and premature wear.